The invention relates to a pharmaceutical packaging comprising a chemically resistant glass that, in particular, is suitable as primary packaging material in the pharmaceutical industry.
There are high demands with respect to such pharmaceutical packagings. In particular a high chemical resistance is important. In addition the glasses used therefor shall be free of delamination, i.e. during use no layers shall separate from the glass which would contaminate the packaged pharmaceutical agent. A main cause for the delamination is the evaporation of alkali borates or boron or alkali-hydro-oxides during the hot-forming to yield pharmaceutical containers. Basically this can be impeded by using boron-free and alkali-free glasses. However, herein basically a problem resists in the fact that in such a case a substantially increased crystallization tendency results which is also detrimental.
Apart from a very good chemical resistance, however there are further demands with respect to glasses that are suitable as primary packaging material in the pharmaceutical industry.
Thus it should be possible to produce the glasses in common melting units, i.e. the viscosity of the melt must not be too high—if possible, the processing temperature (temperature at which the viscosity is 104 dPas, which is also designated as VA or T4) should not exceed the maximum value of 1350° C. For an energy-saving production T4 should be as low as possible.
From EP 0 510 544 A1 alkali-free glasses with the following composition (in wt.-%) are known: 55-65 SiO2, 10-18 Al2O3, 0-3 B2O3, 0-3 MgO, 8-15 CaO, 8-15 SrO and 0-3 ZnO. All examples contain either B2O3 or MgO.
By using B2O3 the delamination tendency is increased which is detrimental for a use as a pharmaceutical packaging. The addition of MgO leads to an increased crystallization tendency which is also detrimental.
EP 2 639 205 A1 discloses alkali-free glasses with the following composition (in wt.-%): 58-70 SiO2, 15.5-20 Al2O3, 0-1 B2O3, 0-5 MgO, 3.5-16 CaO, 0.5-6.5 SrO and 5-15 BaO. These glasses shall be in particular suitable as display glasses.
Herein the high BaO-content which in all examples is at least 5.9 wt.-%, is detrimental, due to the release of Ba2+, which as a heavy metal may give rise to interactions with drugs. In addition the high BaO-content leads to an increased density which increases the cost per kilogram.
From EP 2 650 262 A1 alkali-free glasses with the following composition (in wt.-%) are known: 66-70 SiO2, 12-15 Al2O3, 0-1.5 B2O3, more than 9.5 and 13 or less MgO, 4-9 CaO, 0.5-4.5 SrO, 0-1 BaO and 0-2 ZrO2.
The utilization of high portions of MgO in this glass system leads to an increase of the crystallization tendency which during melting in particular during hot-forming leads to problems or impedes the production of pharmaceutical packagings, respectively.
In JP 05155638 A glasses with the following composition (in wt.-%) are described which shall be in particular usable in combination with resins: 54-62 SiO2, 8-12 Al2O3, 0-5 MgO, 18-22 CaO, 0-5 BaO, 0.5-1.9 TiO2, 0.5-5 ZnO, 0.6-5.0 ZrO2, and 0-1R2O.
In all examples the addition of small amounts of alkali metal oxides (R2O) leads to the formation of easily elusive alkali metal species which also leads to an increase of the delamination tendency. Also MgO is detrimental, since thereby the crystallization tendency is increased. The relatively low Al2O3 content may lead to low resistances against bases.
In US 2014/0377525 A1 substantially alkali-free glasses with the following composition (in mol %) are disclosed: 60-70 SiO2, 9.5-17 Al2O3, 0-9 B2O3, 0-8 MgO, 2-15 CaO, 0.1-10 SrO, 0.5-4 BaO, wherein the molar ratio (CaO+SrO+BaO)/Al2O3 shall be between 0.6 and 1.0.
According to all examples higher portions of B2O3 are contained which leads to an increase in the delamination tendency which is detrimental for a use as a pharmaceutical packaging. The additional MgO present in all embodiments of this system also leads to an increased crystallization tendency which is detrimental for the hot-forming.
From WO 2014/196655 A1 glasses for pharmaceutical packagings with low delamination of the following composition (given in mol %) are known: 69-81 SiO2, 4-12 Al2O3, 0-5 B2O3, 0-10 MgO+CaO+SrO+BaO, 5-20 Li2O+Na2O+K2O, 0.1-12 Li2O.
The utilization of B2O3 as well as the relatively high alkali metal oxide content are main causes for increased delamination which is detrimental for a utilization as a pharmaceutical packaging.
From DE 1 816 391 A1 a glass comprising 59 bis 70 mol % SiO2, 10-20 mol % Al2O3, 12-28 mol % BaO, 0-5 mol % CaO, 0-14 mol % SrO, 0-5 mol % ZnO, 0-3 mol % MgO, 0-2 mol % B2O3 is known which is utilized as a high-temperature glass.
Herein the high content of BaO is detrimental by the release of Ba2+ which as a heavy metal may lead to interactions with drugs. In addition the high contents of BaO lead to an increased density which increases the cost per kilogram.
From U.S. Pat. No. 4,012,263 an alkali-free glass for the electronics industry is known comprising 50-62 wt.-% SiO2, 8-14 wt.-% Al2O3, 15.5-32 wt.-% BaO and at least CaO or MgO, wherein CaO is 0-25 wt.-% and MgO is 0-2.4 wt.-%.
Again the high BaO-content is detrimental.
In addition from EP 0 048 120 A1 a high-temperature-glass for tungsten halogen lamps is known that comprises 64-68 wt.-% SiO2, 11-14 wt.-% CaO, 16.5 to 18.5 wt.-% Al2O3 and a total amount of SrO and BaO of 2-6.5 wt.-%, wherein SrO is 0-4 wt.-% and BaO is 0-5 wt.-%.